After two years as White House “ethics czar,” Norm Eisen is leaving Washington this month to become the U.S. ambassador to the Czech Republic. He will return to his mother’s home country and complete a circle that began more than half a century ago.In Prague, Eisen’s family will move into a home that once served as Nazi headquarters. They will make the kitchen kosher, say blessings in Hebrew and light Shabbat candles on Friday nights. And Eisen will represent the country that adopted his family in the country whose Nazi occupiers tried to extinguish his family.In a gold-hinged frame on Eisen’s White House desk, a pair of black-and-white photographs sits next to a basic Czech language textbook. A young man and woman stare out of the pictures, each younger than Eisen is today. “This is my mom’s passport photo when she came to the United States,” he says. “I think of them every day.”Eisen’s father was born in Poland. His mother is from the former Czechoslovakia. While his father escaped from Europe before World War II began, his mother, Frieda, was deported to the Auschwitz concentration camp in 1944. She was 21.